The treatment of waste, whether generated through municipal collection systems or through a broad range of industries, may be observed to vary from simple land-fill techniques to somewhat sophisticated chemical and biochemical conversion methods. With the latter methods, significant capital commitments generally are called for which require justification by virtue of environmental protection requirements and/or the generation of profitable by-products.
Controlled composting procedures are considered to offer significant promise for providing for an improved disposal of biodegradable industrial and municipal wastes while generating a somewhat valuable by-product. The preferred approach to treatment of wastes by biodegradation is one wherein composting is carried out in the thermophilic phase at temperatures of about 45.degree.-50.degree. C. At such temperatures, bacteria otherwise active in a mesophilic phase at lower temperatures are avoided and noxious odors are not present in the process.
To achieve thermophilic phase digestion, adequate aeration and agitation of the material is required. Generally, the approach to carrying out the thermophilic digestion requiring the lowest capital investment is that of windrowing the waste material. With this approach, long rows of waste are developed which are laterally transferred and, consequently, aerated and agitated by a windrowing device. Thus, the waste material is progressively transferred from one row position to a next, for example, from right to left, across a treatment region over a period of time until a last row position is reached at which point the digestive process is completed and a valuable by-product is available for commercial sale. Such by-products find use, for example, as a surface treatment for strip mine soil reclamation or soil rejuvenation.
The type of windrowing machine currently utilized in industry is one resembling a flight conveyor having a series of parallel, elongate paddles which are mutually interconnected by continuous chains and driven by a hydraulic motor. In operation, a rather large front-end loader is utilized to suspend the conveyor at an angle both with respect to the ground and the axis of the windrow pile while moving forward at a relatively low speed, for instance 1 MPH, such that the lower disposed region or side of the conveyor confronts the row of material and, in effect, thrusts it into an adjacent row. Generally, these rows, which have a width of about 10-12 feet, will be transversely moved such that adjacent rows become spaced about 15 feet apart from center-to-center. The type of front-end loader employed for this procedure necessarily is rather large, typically, a 202 HP loader weighing about 26 tons being utilized.
In the above-described U.S. Pat. No. 4,290,703, apparatus is provided wherein a flight-type windrow conveyor is supported forwardly upon a rigid frame which, in turn, is supported by three freely rotatable wheels. By so positioning these wheels about the frame, the windrow conveyor is properly positioned to confront a row of waste material being transferred, and these supporting wheels of the frame of the apparatus do not encounter the waste. This device is configured for connection with a front-end loader device and may utilize a self-contained motor for providing hydraulic power to the windrow conveyor components. Advantageously, lower powered front-end loaders or the like may be utilized with the improved apparatus. However, during the operation of the apparatus, operators have noticed a "fishtailing" effect which must be accommodated for during performance. Because a windrowing facility may potentially involve the presence of various toxins due, for example, to the loss of aerobic treatment, the physical ground structure uopn which waste treatment takes place is somewhat elaborate. For example, water within the region is fully controlled, underground air ducting is provided as well as water treatment tanks. Thus, minimization of the required area for such for such treatment regions represents an important cost savings. Further, because a continuous waste agitation by windrowing machines is required, a redundancy of machines is needed for each facility to accommodate for any machine breakdown.